Frequency-selective incoherent detection of terahertz radiation by high-Tc Josephson junctions

The detector response of YBa2Cu3O7-x Josephson grain-boundary junctions to monochromatic radiation with the frequency f in the range from 60 GHz to 4 THz has been studied. Frequency-selective odd-symmetric resonances in the responses Delta I(V) of these junctions to radiation with different frequencies f have been observed near the voltages V=hf/2e in almost a decade of spectral range for any operating temperature in the range from 30 to 85 K. The spectral range of the selective detection has scaled with the IcRn product of the Josephson junction, reaching the range of 0.16-3.1 THz for a IcRn product of 1.5 mV. A resolving power delta f/f of around 10(-3) has been demonstrated in the selective detection by Josephson junctions. The high-frequency falldown of the amplitude of the selective response has been found to be proportional to exp[-P/P-0], where P=(hf/2e)(2)/R-n is the power dissipated in the junction at the resonance and P-0 is a characteristic power level. The values of P-0 for our junctions were around 20 mu W at 34 K and 2 mu W at 78 K. (C) 2000 American Institute of Physics. [S0003-6951(00)03720-7].